Postage metering systems print and account for postage and other unit value printing such as parcel delivery service charges and tax stamps. Some of the varied types of postage metering systems are shown, for example, in U.S. Pat. No. 3,978,457 for MICROCOMPUTERIZED ELECTRONIC POSTAGE METER SYSTEM, issued Aug. 31, 1976; U.S. Pat. No. 4,301,507 for ELECTRONIC POSTAGE METER HAVING PLURAL COMPUTING SYSTEMS issued Nov. 17, 1981; U.S. Pat. No. 4,579,054 for STAND-ALONE ELECTRONIC MAILING MACHINE issued Apr. 1, 1986; U.S. Pat. No. 4,559,592 for ELECTRONIC POSTAGE METER HAVING A SWITCHING POWER SUPPLY EMPLOYING INTEGRATED CIRCUIT TIMER issued Dec. 17, 1985; and, U.S. Pat. No. 4,953,996 for PRINT WHEEL SETTING DEVICE FOR A POSTAGE METER issued Sep. 4, 1990. Moreover, other non traditional type of meters have been developed which involve printing systems such as those employing thermal printers, ink jet printers, mechanical pin printers and other types of printing technology. Examples of this latter type of electronic postage meter are described in U.S. Pat. No. 4,168,533 for MICROCOMPUTER MINIATURE POSTAGE METER issued Sep. 18, 1979; and, U.S. Pat. No. 4,493,252 for POSTAGE PRINTING APPARATUS HAVING A MOVABLE PRINT HEAD IN A PRINT DRUM issued Jan. 15, 1985.
Because these postage metering systems print indicia and information having monetary value, the systems must be secure to protect the funds for which they account. Accordingly, various techniques have been formulated and implemented for detecting or precluding fraudulent impressions from being made and for the preclusion of printing of postage without accounting.
The electronic postage meters and mechanical postage meters which include print wheel printing mechanisms usually incorporate die protecting mechanisms as well as shrouds to prevent the "wiping" of postage off the printing mechanism. This is a type of fraud where no accounting occurs because the print wheels are utilized when the meter is inactive to obtain an impression, but with no accounting. This form of fraud is prevented by die protectors which preclude obtaining a firm and positive imprint from the print wheels even if the shrouding which is designed to prevent access to the print wheels is breached. Representative die protecting mechanisms and systems are disclosed in U.S. Pat. No 4,472,625 for SELECTABLE DECIMAL POINT FOR PRINTING DEVICE issued Sep. 18, 1984; U.S. Pat. No. 4,796,526 for VALUE PRINTING DIE PROTECTION DEVICE IN AN ELECTRONIC POSTAGE METER MACHINE issued Jan. 19, 1989; U.S. Pat. No. 4,796,527 for VALUE PRINTING DIE PROTECTION MECHANISM IN A POSTAGE METER MACHINE issued Jan. 10, 1989; and, U.S. Pat. No. 5,020,429 for DIE PROTECTION ASSEMBLY FOR PREVENTING FRAUDULENT PRINTING BY A POSTAGE meter issued Jun. 4, 1991.
Additionally, other systems have been developed particularly for non standard printing technology to help avoid fraudulent imprints. An example of one technique of this type is disclosed in U.S. Pat. No. 4,933,849 for SECURITY SYSTEM FOR USE WITH AN INDICIA PRINTING AUTHORIZATION DEVICE issued Jun. 12, 1990, wherein the indicia printed by the meter may be down loaded to the meter and changed on various dates so that the date the impression is printed can be checked against the particular indicia. Other examples are shown in both U.S. Pat. No. 4,757,537 for SYSTEM FOR DETECTING UNACCOUNTED FOR PRINTING IN A VALUE PRINTING SYSTEM issued Jul. 12, 1988 and U.S. Pat. No. 4,775,246 for SYSTEM FOR DETECTING UNACCOUNTED FOR PRINTING IN A VALUE PRINTING SYSTEM issued Oct. 4, 1988; wherein various encryption techniques are employed to validate the postage metering system indicia.
Further techniques and arrangements for detecting or preventing various fraudulent type attacks on meter system security are disclosed in U.S. Pat. No. 4,931,943 for FRANKING MACHINE PROVIDING A PERIODIC HISTORICAL TRAIL issued Jun. 5, 1990; U.S. Pat. No. 5,075,852 for FRAUD DETECTION IN POSTAGE METER HAVING UNSECURED PRINT WHEELS issued Dec. 24, 1991; U.S. Pat. No. 4,864,618 for AUTOMATED TRANSACTION SYSTEM WITH MODULAR PRINT HEAD HAVING PRINT AUTHENTICATION FEATURE issued Sep. 5, 1989; U.S. Pat. No. 4,780,835 for SYSTEM FOR DETECTING TAMPERING WITH A POSTAGE VALUE ACCOUNTING UNIT issued Oct. 25, 1988. All of these patents deal with the issue of detecting or preventing a fraudulent postage imprints.
It has been recognized that the various postal services (as well as private carrier services), however, can also be defrauded through the short payment of mail. The short payment of mail can occur when either intentionally or unintentionally a postage meter system user imprints an improper amount of postage on a mail piece which does not meet the requirements of the postal system for the country involved. Overpayment of mail can also occur in a similar manner, as for example, by the use of wrong postal rate tables. For example, in most countries, such as the United States, the postage payment system is based on a physical characteristic of the mail piece and the class of service in which the mail piece is being delivered. In the United States, first class mail, at the present time, requires a postage payment of 29 cents for the first half ounce and 23 cents for each half ounce thereafter. Thus, for first class mail, a postage value under 29 cents would be less than the legally acceptable minimum value. Moreover a postage value of 51 cents or 73 cents or 74 cents would not be appropriate postage values for first class mail. Other examples of tables for the United States Postal Service are set forth in section 411.352 of the Mar. 15, 1992 Domestic Mail Manual (DMM). Postage payment for second class mail would be susceptible to the same type problem as first class mail. Moreover use of a first class rate table by a mailer when the second class rate table is applicable would result in overpayment by the mailer for a mail piece. There are, of course, other parameters that can be utilized such as mail piece size, or non physical parameter type characteristics for mail pieces (which should be recognized to include parcels) such as distance (ZIP code of recipient or zone of recipient) for parcel delivery services.
The above type difficulty of improper payment (whether it be under payment to the postal service or overpayment by the user), have been recognized as a problem requiring attention. The U.S. Pat. No. 5,019,991 for CERTIFIED WEIGHER-SHORT PAID MAIL issued May. 28, 1991 provides a system for certifying correctly accounted for postage payment wherein documents are fed along a document path in certain parameters for documents are determined (such as weight). A printer under control of the data processor then places a certification imprint upon the document after necessary accounting is done. The certification can be a certified weighing means for weighing mail pieces with data processing means coupled to the accounting means and the weighting means for determining postage required for mailing the mail pieces. Moreover, as disclosed in pending U.S. patent application Ser. No. 952,071 for MAIL PROCESSING SYSTEM FOR VERIFYING POSTAGE AMOUNT filed on Sep. 25, 1992, for Flavio M. Manduley and Leon A. Pintsov, and assigned to Pitney Bowes Inc.; a mail stream is run through a certifying system which puts an additional imprint on the mail piece to indicate whether or not the first impression by the user is appropriate for the particular mail pieces. Another system to help avoid improper payment is described in pending U.S. patent application Ser. No. 986,231 for POSTAGE METERING SYSTEM WITH INDICIA SELECTABLE TO COMPENSATE FOR DETECTED PRINTER DEFECTS filed on Dec. 7, 1992 for Wallace Kirschner and Arno Muller and assigned to Pitney Bowes, Inc.
While the above systems work satisfactorily for their intended purposes and provide increased security for the avoidance of postal fraud, it is desirable to provide enhanced systems further simplifying the detection of improper postage payment. Moreover, it is desirable to provide such increased security for both the more traditional mechanical printing postage meter mechanisms as well as the non-traditional postage meter printing technologies.